1. Field of the Invention
The present invention relates to a motion sensor for detecting a bearing and an acceleration, and to a portable telephone using such a motion sensor.
2. Description of the Related Art
An attitude detection sensor for detecting a bearing and a tilt is known, which is composed of a combination of a 3-axis magnetic sensing part and a 2- or more axis acceleration sensing part. More specifically, such an attitude detection sensor is constituted, a magnetic sensing part using a Hall device and an acceleration sensing part including a stress sensing element for detecting displacement of a weight which moves depending on a gravitational force applied to the weight (as disclosed, for example, in Patent Document 1).
However, the conventional attitude detection sensor has the following problems. In this attitude detection sensor, because the magnetic sensing part and the acceleration sensing part are based on different measurement principles, it is difficult to achieve an efficient disposition of these sensors, and thus it is difficult to achieve miniaturization of total size of an attitude detection sensor. Besides, the magnetic sensing part and the acceleration sensing part need completely different electronic circuits for processing signals output from these sensors. The necessity for two different types of electronic circuits also makes it difficult for the attitude detection sensor to have a sufficiently small size. Also, if the acceleration sensing parts are disposed to be adaptable for only two-axis directions, it is difficult to accurately detect acceleration in all directions.
[Patent document 1] JP 2003-172633 Unexamined Patent Publication (Kokai)
In view of the above-mentioned problems with the related art, an object of the present invention is to provide a motion sensor which can easily and accurately detect bearing, attitude and acceleration in any of three-dimensional directions.